The present invention addresses the problem of providing a method for suppressing differentiation of ganglion cells, amacrine cells, horizontal cells, and/or bipolar cells in neural retinal tissues including photoreceptor precursor cells and/or photoreceptor cells, etc. This method for suppressing differentiation of ganglion cells, amacrine cells, horizontal cells, and/or bipolar cells in neural retinal tissues including photoreceptor precursor cells and/or photoreceptor cells comprises a step for culturing, in a medium containing a thyroid hormone signal transduction pathway active substance, retinal tissues that contains neural retinal precursor cells and are in any one of differentiation stages from a differentiation stage just after the emergence of ganglion cells to a stage at which the occurrence rate of pyramidal photoreceptor precursor cells reaches the maximum.
